<!DOCTYPE html>
<head>
    <meta charset="UTF-8">
    <title>边框宽度</title>
    <style type="text/css">
        div{
            background-color: red;
            width:500px;
            height:500px;
            border-style:double;
            border-width:10px 20px 30px 40px;/*10px 20px|10px 20px 30px*/
            /* border-top-width:10ox;
            border-right-width:20px;
            border-bottom-width:30px;
            border-left-width:40px; */
        }
    </style>
</head>
<body>
    <div></div>
</body>
</html>